Unpredictable

"This is the newest model," said the salesman. A red-skinned demon clung to the top, tiny ebony claws blending with the perfect blackness of the screen. "It uses quantum computing and has tons of, um, memory gigs. Very fast. Very powerful."

The imp cocked its head and stared at Brad. "When the world burns, I will lick the filth from your intestines."

"That, um, that's just quantum... foam... flux," the salesman explained. "You should disregard anything it says. Standard quirk. The perils of early adoption!" He chuckled weakly.

The imp's tongue was black. It blinked in time with Brad's heartbeats.